By way of introduction, a current routing metric for a given link is generally treated as a constant, non-dynamic value, which is often based on link speed e.g., bandwidth, without regard to the other underlying link attributes. Even when other attributes are considered, the other attributes are typically provided manually and with static configurations, which may or may not accurately represent the underlying link attributes at a given moment. To influence metric computation, routing operators statically configure a cost value to represent link attributes. By way of example, Enhanced Interior Gateway Routing Protocol (EIGRP) defines a static interface delay as a component of its metric calculation.
Layer 3 services today are often built over a wavelength division multiplexing (WDM) based optical infrastructure in a multilayer network, which may consist of multiple paths in each layer. The multiple paths of the optical network are commonly built with colorless directionless contentionless (CDC) reconfigurable optical add drop multiplexer (ROADM) nodes. Multilayer optical networks typically support dynamic wavelength routing during initial optical circuit provisioning, which means accurate circuit attributes are unknown prior to the circuit creation.